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      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.example.android.newsreader;
     18 
     19 import android.app.ActionBar.OnNavigationListener;
     20 import android.app.ActionBar.Tab;
     21 import android.app.ActionBar.TabListener;
     22 import android.app.FragmentTransaction;
     23 
     24 /**
     25  * Adapter for action bar navigation events.
     26  *
     27  * This class implements an adapter that facilitates handling of action bar navigation events.
     28  * An instance of this class must be installed as a TabListener or OnNavigationListener on an
     29  * Action Bar, and it will relay the navigation events to a configured listener
     30  * (a {@link CompatActionBarNavListener}).
     31  *
     32  * This class should only be instanced and used on Android platforms that support the Action Bar,
     33  * that is, SDK level 11 and above.
     34  */
     35 public class CompatActionBarNavHandler implements TabListener, OnNavigationListener {
     36     // The listener that we notify of navigation events
     37     CompatActionBarNavListener mNavListener;
     38 
     39     /**
     40      * Constructs an instance with the given listener.
     41      *
     42      * @param listener the listener to notify when a navigation event occurs.
     43      */
     44     public CompatActionBarNavHandler(CompatActionBarNavListener listener) {
     45         mNavListener = listener;
     46     }
     47 
     48     /**
     49      * Called by framework when a tab is selected.
     50      *
     51      * This will cause a navigation event to be delivered to the configured listener.
     52      */
     53     @Override
     54     public void onTabSelected(Tab tab, FragmentTransaction ft) {
     55         // TODO Auto-generated method stub
     56         mNavListener.onCategorySelected(tab.getPosition());
     57     }
     58 
     59     /**
     60      * Called by framework when a item on the navigation menu is selected.
     61      *
     62      * This will cause a navigation event to be delivered to the configured listener.
     63      */
     64     @Override
     65     public boolean onNavigationItemSelected(int itemPosition, long itemId) {
     66         mNavListener.onCategorySelected(itemPosition);
     67         return true;
     68     }
     69 
     70 
     71     /**
     72      * Called by framework when a tab is re-selected. That is, it was already selected and is
     73      * tapped on again. This is not used in our app.
     74      */
     75     @Override
     76     public void onTabReselected(Tab tab, FragmentTransaction ft) {
     77         // we don't care
     78     }
     79 
     80     /**
     81      * Called by framework when a tab is unselected. Not used in our app.
     82      */
     83     @Override
     84     public void onTabUnselected(Tab tab, FragmentTransaction ft) {
     85         // we don't care
     86     }
     87 
     88 }
     89